Electric toothbrush head

ABSTRACT

A head for an electric toothbrush includes a support member having a plurality of holes extending completely therethrough. A plurality of tufts of bristles each extends through one of the holes. A first brushing end of each tuft projects from a first side of the support member. Each tuft is prevented from being withdrawn from its hole when a tensile force is applied to the first end of each tuft along a long axis of the tuft. A resilient cushion is positioned adjacent a second side of the support member such that a second end of each tuft can contact the cushion. When a compressive force is applied to the first end of each tuft along the long axis of each tuft, each tuft can move in its hole in a first direction into the cushion. When the compressive force is removed the cushion causes each tuft to move in its hole in a second direction substantially opposite the first direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/824,310filed on Apr. 2, 2001, which is herein incorporated by reference.

FIELD OF THE INVENTION

The invention relates generally to the field of oral care, and inparticular to toothbrushes. More specifically, the invention relates toelectric toothbrushes.

BACKGROUND OF THE INVENTION

Electric toothbrushes are well known and have been on the market foryears. With typical electric brushes all of the tufts of bristles on thebrush head are vertically oriented relative to the top surface of thehead. The tufts are oscillated, rotated and/or translated in order toprovide enhanced tooth cleaning capability.

German Gebrauchsmuster 8807968.6 discloses a head for an electrictoothbrush. A first group of circular tufts 18 are arrayed in a firstring about the center of rotation of the head. A second group of tallercircular tufts 16 are arrayed in a second ring which is outside thefirst ring and also encircles the center of rotation of the head. All oftufts 16 and 18 are circular in cross-section and are canted away fromthe center of the head at an acute angle relative to a top surface ofthe head

A problem with this brush is that all of the tufts have a circularcross-section. Such tufts are not that effective at penetrating betweenteeth to clean the interdental or approximal areas of the teeth.Further, all but one of the tufts are angled away from the center. Sucha tuft pattern tends to flair (flatten) out even more than designedduring use, thereby having the same brushing characteristics as aworn-out standard brush. Additionally, none of the tufts are angledalong the direction of the rotational circumference which results ineven poorer interdental penetration of the bristles.

European Patent 0765642 also discloses a head for an electrictoothbrush. There are a number of bristle tufts 17 which are verticallyoriented on the head. Bristle tufts 13, 15 are located about a perimeterof the circular head and are tilted at an acute angle along acircumference of a top surface of the head. All of the tufts on the headhave a circular cross-section.

Again we see the problem of a brush head in which all of the tufts havea circular-cross-section: such tufts do not penetrate well in theapproximal tooth areas. This head also has no tufts which are angledaway from the center to sweep along the gum line or gingival margin ofthe mouth. Further, in two pairs of the tufts 13, the tufts are adjacentto each other and are angled towards each other. These two tufts appearto be in contact. A downside to this tuft arrangement is that the twoadjacent tufts can tend to interfere with each other during use of thebrush. In addition, due to the tuft configuration and shape, a lot ofthe available space of the head is not used. This reduces efficacy andincreases wear of the head (flare) upon use. For effective brushingapproximately 32-36% of the head surface must be covered withtufts/bristles.

SUMMARY OF THE INVENTION

The present invention is directed to overcoming one or more of theproblems set forth above. Briefly summarized, according to one aspect ofthe present invention, a head for an electric toothbrush includes asupport member and a plurality of tufts of bristles supported at theirbase by the support member. Two of the tufts have their bases adjacentto each other and are tilted away from each other at an acute anglerelative to the support member.

According to a second aspect of the invention, a head for an electrictoothbrush includes a support member having a plurality of holesextending completely therethrough. A plurality of tufts of bristles eachextends through one of the holes. A first brushing end of each tuftprojects from a first side of the support member. Each tuft is preventedfrom being withdrawn from its hole when a tensile force is applied tothe first end of each tuft along a long axis of the tuft. A resilientcushion is positioned adjacent a second side of the support member suchthat a second end of each tuft can contact the cushion. When acompressive force is applied to the first end of each tuft along thelong axis of each tuft, each tuft can move in its hole in a firstdirection into the cushion. When the compressive force is removed thecushion causes each tuft to move in its hole in a second directionsubstantially opposite the first direction.

According to a third aspect of the invention, a head for an electrictoothbrush includes a support member and a plurality of tufts ofbristles supported at their base by the support member. The supportmember has a substantially circular surface from which the tuftsproject. A first one of the tufts is tilted along an imaginary radiuswhich projects from a center of the circular surface and passes througha base of the first tuft. A second one of the tufts is tilted along animaginary circumference which encircles the center of the circularsurface and passes through a base of the second tuft.

According to a fourth aspect of the invention, a head for an electrictoothbrush includes a support member and a plurality of tufts ofbristles supported at their base by the support member A pair of thetufts is tilted in substantially the same direction relative to thesupport member. A first tuft of the pair has a different cross-sectionthan a second tuft of the pair.

These and other aspects, objects, features and advantages of the presentinvention will be more clearly understood and appreciated from a reviewof the following detailed description of the preferred embodiments andappended claims, and by reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a portion of an electric toothbrush;

FIG. 2 is a is an exploded view of FIG. 1;

FIG. 3 is a front view of FIG. 1 looking along the direction of arrow 3;

FIG. 4 is a side view of a cushion, support member and tuft of bristlesof the toothbrush of FIG. 1;

FIG. 5 is a perspective view of a second embodiment of a head for anelectric toothbrush;

FIG. 6 is an enlarged top view of the head of FIG. 5;

FIG. 7 is a sectional view of FIG. 6 taken along lines A-A;

FIG. 8 is a sectional view of FIG. 6 taken along lines B-B; and

FIG. 9 is a sectional view of FIG. 6 taken along lines D-D.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

Beginning with FIGS. 1 and 3, an electric toothbrush 10 includes a neck12 and a head 14. As is well known to those skilled in the art, head 14is oscillated through an angle of preferably ±20 to 50 degrees about anaxis parallel to an arrow 3. Electrical power is preferably supplied byrechargeable or single use batteries. The batteries power an electricmotor which, through gearing or another linking element, oscillates thehead. Further details as to how the head is oscillated will not beprovided as this aspect of the brush is not the focus of the invention.

Head 14 contains a large number of tufts of varying lengths,cross-sections and orientations. Although each tuft is shown as a solidmass in the drawings, the tufts are actually each made up of a greatmass of individual plastic bristles. The bristles are preferably made of612 nylon. Each of tufts 16 are oval in cross-section with a 6.1 mmheight. The dimensions of the oval are 1.78 mm×3.05 mm. 5 or 6 milfilament can be used for tuft 16. The tuft is vertically orientedrelative to the top surface of the head.

Each of tufts 18 are triangular in cross-section with rounded vertexes(tri-oval in shape). These tufts are 6.35 mm in height with a dimensionof 2.03 mm from the rounded vertex nearest the center of the head to itsopposite side. Tufts 18 also have a dimension of 2.28 mm between the tworemaining rounded vertices. Preferably 6 mil filament is used to makethe bristles for this tuft. The tuft is vertically oriented relative tothe top surface of the head.

Each of tufts 20 are oval in cross-section with a 7.62 mm height. Thedimensions of the oval are 1.27 mm×2.28 mm. 6 mil filament can be usedfor tufts 20. The tuft is tilted away from the center of the head at anangle of about 20 degrees relative to the top surface of the head. Thelong dimension of the oval cross-section lies along the direction oftilt of tuft 20.

Each of tufts 22 are oval in cross-section with a 7.37 mm height. Thedimensions of the oval are 0.76 mm×3.05 mm. 6 mil filament can be usedfor tufts 22. The tuft is tilted along an imaginary circular line whosecenter is concentric with the head's center. The angle of tilt is about20 degrees relative to the top surface of the head. The long dimensionof the oval cross-section is aligned substantially towards the center ofthe head.

Each of tufts 24 are oval in cross-section with a 7.62 mm height. Thedimensions of the oval are 0.76 mm×1.52 mm. 6 mil filament can be usedfor tufts 22. The tuft is tilted along an imaginary circular line whosecenter is concentric with the head's center. The angle of tilt is about12 degrees relative to the top surface of the head. The long dimensionof the oval cross-section is aligned substantially towards the center ofthe head.

Each of tufts 24 are oval in cross-section with a 7.62 mm height. Thedimensions of the oval are 0.76 mm×1.52 mm. 6 mil filament can be usedfor tufts 22. The tuft is tilted along an imaginary circular line whosecenter is concentric with the head's center. The angle of tilt is about12 degrees relative to the top surface of the head. The long dimensionof the oval cross-section is aligned substantially towards the center ofthe head.

Each of tufts 26 are oval in cross-section with a 8.4 mm height. Thedimensions of the oval are 0.76 mm×1.52 mm. 6 mil filament can be usedfor tufts 22. The tuft is tilted along an imaginary circular line whosecenter is concentric with the head's center. The angle of tilt is about12 degrees relative to the top surface of the head. The long dimensionof the oval cross-section is aligned substantially towards the center ofthe head.

Turning now to FIG. 2, a more detailed description of head 14 will beprovided. A plastic base member 30 is supported in neck 12 and is drivenby gearing or another driving element (not shown) to oscillate the head.A resilient cushion 32 is made of a thermoplastic elastomer and ispositioned within base member 30. A plastic support member 34 has anumber of wholes therethrough which match in number and shape the numberand shape of all of the tufts of bristles. Base member and supportmember can be made of Delrin. Cushion 32 can be made of GLS Dynaflex G6703

A pair of catches 36 (only one is visible) in support member 34 engage apair of openings 38 in base member 30 to secure the support member tothe base member in a snap-fit arrangement which securely traps cushion32 therebetween. Tufts 40 are supported at their bases by the supportmember. The lower portions of the tufts are not shown in FIG. 2 but willbe described in further detail below.

Referring to FIG. 4, cushion 32 is shown adjacent support member 34.Only one of the tufts 18 is shown. The non-brushing end of tuft 18 hasbeen melted into a mass 42. Mass 42 prevents tuft 18 from beingwithdrawn from its hole when a tensile force is applied to a brushingend 43 of the tuft along a long axis of the tuft. A cylindrically shapedprotrusion 44 is provided on cushion 32 and is in contact with mass 42.At least one protrusion is provided for each tuft on the brush.

When a compressive force is applied to end 43 of tuft 18 along the longaxis of the tuft, the tuft can move in its hole in a first direction 46into the cushion. Such movement occurs because protrusion 44 acts like aspring, compressing under the force applied to it by mass 42. When thecompressive force is removed the protrusion resumes its original shape,causing tuft 18 to move in its hole in a second direction substantiallyopposite the first direction. Such action assists in preventing damageto a person's gums in the event excessive pressure is used duringbrushing of the teeth.

Alternatively, mass 42 can be captured within support member 34 whilethe support member is being formed by injection molding (known ashot-tufting). In this case, cushion 32 is not required. In anotheralternative, member 34 is ultrasonically welded to base member 30 afterthe tufts are secured to member 34. As such, catches 36 and openings 38are eliminated.

Embodiment 2

Turning now to FIGS. 5-9, a second embodiment of a head for an electrictoothbrush will be described. A head (support member) 50 supports amultiplicity of tufts of bristles. The bristles all have a diameter ofabout 6mil. Of course different filament diameters can be used (e.g.6.0±0.5 mil).

A first group of tufts 52 have a round cross-section and extendperpendicular from head 50. Each tuft includes about 54 bristles pertuft. Tufts 52 rise about 7 mm above the head (the tufts' length) andpreferably include bi-filament bristles. Such bristles are coextrudedfrom two different materials, such as nylon 6.12 and nylon 6.10, andbend when exposed to water. All nylons mentioned for this embodiment arepreferably polyamid. Further details on such bi-filament bristles can befound in PCT published application WO 98/14092.

A second group of tufts 54 are oval in shape (i.e. fin shaped) and alsoextend perpendicular from head 50. The filaments of this tuft areextruded from a single material such as nylon 6.12 Tufts 54 rise about7.4 mm above the head. There are about 108 bristles in each tuft 54.

A third group of tufts 56 are also oval in shape and rise about 7.4 mmabove head 50. Tufts 56 are preferably made of nylon 6.12 with each tuftincluding about 108 bristles. Tufts 56 are angled away from vertical byabout 6 degrees in a radial direction away from the center of the head(see FIG. 8).

A fourth group of tufts 58 are round in cross-section and rise about 7.4mm above head 50. Such bristles are coextruded from two differentmaterials, such as nylon 6.12 and nylon 6.10, and bend when exposed towater. Each tuft includes about 54 bristles. Tufts 58 are angled awayfrom vertical by about 7.5 degrees in a radial direction away from thecenter of the head (see FIG. 8).

A fifth group of tufts 60 are oval in cross-section and rise about 8.3mm above head 50. Tufts 60 are preferably made of nylon 6.12 with eachtuft including about 108 bristles. Tufts 60 are angled away fromvertical by about 7.5 degrees in a tangential (i.e. circumferential)direction. Each tuft 60 is angled towards its closest neighboring tuft60 (see FIG. 8) which makes the tufts more stable because the pairedtufts support each other during brushing. This also assists in reducingbristle wear for these tufts.

A sixth and final group of tufts 62 are round in cross-section and riseabout 7.4 mm above head 50. Tufts 62 are preferably made of nylon 6.12with each tuft including about 54 bristles. Tufts 62 are angled awayfrom vertical by about 6 degrees in a tangential (i.e. circumferential)direction. Each tuft 62 is angled towards its closest neighboring tuft62 (see FIG. 5).

Endrounding of the bristles is accomplished after they are secured tothe head. As such, the angle of tilt away from vertical for applicabletufts is limited to 7.5 degrees in order to obtain the best endrounding.Conventional stapling techniques can be used to secure the single tuftsor segments to the head at an angle up to 7.5 degrees. If a tuft angleabove 7.5 degrees is desired, an additional degree of freedom isrequired for the stapling tool (in this case, endrounding will not be asgood).

Tufts 56 and 60 preferably include blue or green wear indicatingbristles which are described in detail in U.S. Pat. No. 4,802,255. Ovalshaped tufts 54, 56 and 60 are actually each made up of two groups ofbristles. The oval shape increase the stiffness of these tufts andallows them to penetrate better between teeth than circular tufts.. Allof the oval shaped tufts have dimensions of about 1.45 mm by 2.9 mm Allof the tufts with round cross-sections have a diameter of about 1.5 mm.The diameter of head 50 is about 13.25 mm. In an alternative embodiment,all of the tufts on the head range in length (the rise above the head)between about 6.7 mm to about 8.6 mm.

The invention has been described with reference to preferredembodiments. However, it will be appreciated that variations andmodifications can be effected by a person of ordinary skill in the artwithout departing from the scope of the invention.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by referenced, themeaning or definition assigned to the term in this written documentshall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A head for an electric toothbrush, comprising: a support member; anda plurality of tufts of bristles supported at their base by the supportmember, two of the tufts having their bases adjacent to each other, thetwo tufts being tilted away from each other at an acute angle relativeto the support member.
 2. The head of claim 1, wherein at least one ofthe two tufts has a cross-section which is other than round in shape. 3.The head of claim 1, wherein at least one of the two tufts has across-section which is oval in shape.
 4. The head of claim 1, whereinthe plurality of tufts includes a third tuft which has a differentcross-section than either of the two tufts.
 5. The head of claim 4,wherein the third tuft is also tilted at an acute angle relative to thesupport member.
 6. A head for an electric toothbrush, comprising: asupport member having a plurality of holes extending completelytherethrough; a plurality of tufts of bristles, each tuft extendingthrough one of the holes, a first brushing end of each tuft projectingfrom a first side of the support member; means for preventing each tuftfrom being withdrawn from its hole when a tensile force is applied tothe first end of each tuft along a long axis of the tuft; and aresilient cushion positioned adjacent a second side of the supportmember such that a second end of each tuft can contact the cushion,whereby when a compressive force is applied to the first end of eachtuft along the long axis of each tuft, each tuft can move in its hole ina first direction into the cushion, and when the compressive force isremoved the cushion causes each tuft to move in its hole in a seconddirection substantially opposite the first direction.
 7. The head ofclaim 6, wherein the preventing means includes a thickened portion atthe second end of each tuft, the thickened portion being larger than thetuft's respective hole such that the thickened section cannot be pulledthrough the hole.
 8. The head of claim 6, wherein two of the tufts aretilted away from each other at an acute angle relative to the supportmember.
 9. The head of claim 6, wherein at least one of the tufts has across-section which is oval in shape.
 10. A head for an electrictoothbrush, comprising: a support member; and a plurality of tufts ofbristles supported at their base by the support member, the supportmember having a substantially circular surface from which the tuftsproject, a first one of the tufts being tilted along an imaginary radiuswhich projects from a center of the circular surface and passes througha base of the first tuft, a second one of the tufts being tilted alongan imaginary circumference which encircles the center of the circularsurface and passes through a base of the second tuft.
 11. The head ofclaim 10, wherein a base of the first tuft is located closer to thecenter of the circular surface than a base of the second tuft.
 12. Thehead of claim 10, wherein the first tuft and second tuft are tilted atdifferent angles relative to the circular surface.
 13. The head of claim10, wherein at least one of the first and second tufts has across-section which is other than round in shape.
 14. The head of claim10, wherein at least one of the first and second tufts has across-section which is oval in shape.
 15. A head for an electrictoothbrush, comprising: a support member; and a plurality of tufts ofbristles supported at their base by the support member, a pair of thetufts being tilted in substantially the same direction relative to thesupport member, a first tuft of the pair having a differentcross-section than a second tuft of the pair.
 16. The head of claim 15,wherein the first tuft has a different length than the second tuft. 17.The head of claim 16, further including a third tuft which is tiltedrelative to the support member, the third tuft having a different lengththan the first and second tufts.
 18. The head of claim 15, wherein thefirst tuft has a different number of bristles than the second tuft. 19.The head of claim 15, wherein the first tuft has a different length thanthe second tuft.
 20. The head of claim 15, further including a thirdtuft which is tilted a an angle which is different from the angle oftilt of the first and second tufts.
 21. The head of claim 6, wherein atleast one of the tufts is oriented at an acute angle to a surface of thesupport member from which the at least one tuft projects.